Thanks for posting this latest RCT, abnk. Fr Nix's discussion is very interesting.
I've heard a Catholic priest of the Byzantine Rite identify Gehenna with purgatory, at a parish Bible study from about ten years ago.
Much of this teaching from Trent has been new to me since my seminary studies. As the Orthodox Church's position is pretty reticent when it comes to describing much in the way of specifics on the afterlife, beyond that the soul in eternity will either be in God's kingdom or outside it. Historically in the East there is the basic acceptance of an intermediate state (allegorically toll houses that some compared to purgatory, such as Patriarch of Constantinople Gennadios Scholaros). More recently, this intermediate (toll houses) state has been supported by St Ignatius Brianchaninov and St. Seraphim Rose.